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ABB drives have reduced the need for Thermphos, a manufacturer of specialist chemicals, to replace gears on its product kiln, saving GBP18,000 each time.

Thermphos manufactures special chemicals used in a variety of applications, including pharmaceuticals, hygiene, industrial cleaning, household cleaning, food additives and feed additives.

The company’s six products are produced in a rotating kiln, each made at its own temperature.

The different production characteristics of the products lead to a wide temperature range experienced by the kiln, which, at the highest temperatures, can produce a 40mm expansion of the kiln compared with its dimensions at the lowest temperature.

This expansion caused problems because the kiln was originally driven by a girth gear around its circumference.

Thermal expansion meant that the gears were threshing, leading to high wear and a need to replace them frequently.

Mike Organ, works engineer for Thermphos, said: ‘The gears cost GBP18,000 to replace and we needed to replace them, on average, about every two years.

‘It was also becoming increasingly difficult to source companies with the expertise to make these large gear assemblies,’ he added.

Another difficulty was reversing the kiln to remove the product at the end of the process.

The increased forces caused by the unloading mechanism could throw the kiln off its supporting trunnion rollers.

Thermphos asked ABB Drives Alliance member Halcyon Drives to design a solution.

The power transmission rotating the kiln was updated and redesigned using two motorised gear units driving friction rollers to rotate the kiln drum and was controlled by two ABB industrial drives in master/follower control, allowing load sharing.

Using two driven rollers ensures that heat-induced movement can be tolerated, allowing a wider range of production temperatures.

Employing a master/follower arrangement also cuts the need for a feedback encoder, which could be affected by the dusty conditions.

Another advantage is the ability to reverse the kiln direction more easily, allowing it to be emptied more quickly.

Organ continued: ‘With the new system, we don’t have to worry about gears.

‘We no longer have the major replacement costs and we can run the kiln at any speed we need, using less power,’ he said.

ABB Automation Tech – Drives and Motors

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